A group of researchers at the University of Massachusetts at Amherst proposes to purchase a Leica TCS SP-2 confocal microscope system. The new confocal microscope will replace an outmoded 14-year old BioRad 600/1000 instrument which cannot support the critical needs of the group for multi-wavelength excitation, time-resolved live cell imaging, and fluorescence recovery after photobleaching (FRAP). The instrument will be housed in the Central Microscopy Facility, a fee-based shared facility for the life sciences research community which receives a generous subsidy from the university administration in support of two full-time professional microscopists and instrument maintenance. One of the staff members has been responsible for the present confocal microscope since 1994, and has extensive skills and experience in optics, digital imaging, and computer interfaces. He will be responsible for the new Leica confocal, both in terms of user training and maintenance. As further commitment to the Facility, the Vice Chancellor for Research will fund a new technical position, whose major duties will include day-to-day instrument care and assisting confocal users following their initial training. The components of the new instrument have been selected to meet the specific needs of a core of 8 major and 7 minor users, 11 of whom have current NIH support. A Leica DM IRBE inverted microscope has been chosen for optimal microinjection capability, and the HeNe and Ar laser combination will provide the needed range of excitation wavelengths. Projects requiring advanced confocal imaging in support of the specific aims of NIH awards include: cytoskeletal dynamics during mitosis, the sorting of proteins in melanoma cells, the development of neuromuscular junctions, the mechanism of programmed cell death in Tlymphocytes, and the role of the actin cytoskeleton in pollen tube growth.